Today, stringent water quality standards are imposed by Federal Regulations governing the effluent limits of treatment facilities. Current criteria specify a DO concentration between 3 and 6 mg/l, depending on the receiving stream requirements. Most existing wastewater treatment facilities cannot meet the newly implemented DO criteria. Consequently, post-aeration measures must be added for compliance with these criteria and regulations, and is often desirable for various water treatment systems regardless of the requirements of the system(s).
Several known post-aeration methods have been employed for oxygen transfer. In general, the most common methods involve various types of mechanical or conventional cascade aeration. Each of these methods has the disadvantage of being an expensive addition to existing wastewater treatment facilities. For example, mechanical aeration requires the addition of an aeration basin with adequate liquid retention capacity for oxygen infusion by electrically powered aeration equipment. This is a less desirable method of boosting oxygen levels in the liquid, but in the past was the only available solution. There are also two aggravating cost factors involved with mechanical aeration: the high initial investment for the basin and equipment, and the ongoing maintenance and operating expense.
In general, cascade post-aeration installations are more desirable and cost effective. There is no power consumption or maintenance expense, the primary requirement for the application of a cascade aerator being sufficient elevation to produce a waterfall. The normal requirement for oxygen transfer through prior art cascade aeration is twelve inches of water fall for each mg/l increase. For example, to raise the oxygen concentrations in water by 6 mg/l, a minimum fall of six feet is typically required. However, most existing facilities lack ample elevation change for the utilization of prior art cascade aerators and it would unnecessary expense to create the required elevation change is an established facility.
Therefore, a present need is felt to provide an improved cascade aerator assembly that comprises a plurality of transversely oriented baffles, which in a preferred embodiment are spaced apart from the floor or “trough” of the cascade aerator. Other benefits and advantages will become known upon reviewing the Summary and Detailed Description below, and upon review of the appended drawing figures. The benefits, embodiments, and/or characterizations described herein are not necessarily complete or exhaustive, and in particular, as to the patentable subject matter disclosed herein. Other benefits, embodiments, and/or characterizations of the present disclosure are possible utilizing, alone or in combination, as set forth above and/or described in the accompanying figures and/or in the description herein below.